I don't pretend to understand in real depth what caused the Great Financial Crisis. I've tried, but eventually talk of 'quantitative easing', 'stagflation' and 'toxic debt' make my head spin (what do you MEAN 'The value of money?') and my neurons all fling up tiny STOP signs in protest.

Still, I do understand, and it is generally accepted now, that at the core of the mess was a kernel of swagger, and that swagger belonged to a bunch of alpha, competitive and overconfident Wall Street bankers. Male ones, it should be pointed out - because if the bankers had been women the recession would likely never have happened.

That's according to Po Bronson and Ashley Merryman, authors of the new book Top Dog: The Science of Winning and Losing, who say the GFC is a direct result of too much testosterone.

"You might think everyone would've jumped on this," said Bronson to the New York Post this week.

"Here's this thing that explains the financial crisis!"

Bronson and Merryman hinge their theory partly on a 2010 study by Dr Alok Kumar at the University of Texas. Dr Kumar had witnessed several studies that showed female CFOs were invariably better at maximising revenue than male CFOs, and wanted to know how this might apply to Wall Street.

So he trawled through Thomson Reuters' International Brokers Estimate System with a fine-toothed comb, studying every single projection made by every Wall Street analyst in the period 1983 (when ladies began to play with the numbers also, and not just as typists) to 2006.

Basically, Dr Kumar found women were consistently more right than men (by 7.3 per cent) despite women's lesser experience on the trading floor. What's more, female analysts out-analysed their male counterparts in 33 out of 48 different market industries. In short, ladies were Wall Street whizzes. The numbers didn't lie - it was plain as day.

His study spurred offshoots in Europe, which found the same thing: Men were more likely to take big chances and encourage companies to take bold risks, whereas women tended to jump only when a soft landing looked more likely, resulting in favourable results.

This can be explained by the differences between male and female brains, say Bronson and Merryman. They point to former trader and neuroscientist John Coates, who, in 2010, said the testosterone overload at Wall Street has serious implications: "Women have only 10 per cent of the testosterone men have," he explained. "If there were more women... there might be more stability."

Which is a fair point: Studies show bankers' testosterone spikes when their trading goes well, amping up their hunger for risk and lowering their capacity for critical thinking. Inversely, women have less 'optimism bias' - or, less of the 'I don't know for sure, but I'm probably right' gene. And not nearly as much testosterone to cloud that cautionary instinct.

Why, then, are 84 per cent of Wall Street analysts still male? And why are only three per cent of Wall Street's top executives women? Surely there are more female graduates than that coming out of university and wanting a piece of it.

One report shows that when it came to getting onto the Street, it's what you know for female analysts and who you know for their male counterparts. Which might explain why the women who do get through are so capable, but also why there are less of them. Last-bastion boys' club are no easy nut to crack.

Ilene Lang - CEO of Catalyst, a research organisation working to advance women into business leadership - recently told the New York Times that:

"The Wall Street culture is characterised by what you might call really macho kinds of behaviour. So what's looked up to on Wall Street are people who swagger, people who will do the deal at any cost, people who will work day and night, hour and hour, for lots and lots of money, and they don't care about anything else.

"That's a very masculine, macho culture, again a stereotype, and, in general, it's very hard for women or men to picture women being that way, because that conflicts with the stereotypic norms of what women should be like."

It's called stereotypic bias: traits belonging to one gender become the benchmark of success. Exacerbating this is the lack of female role models for women in finance, and the fact that the role models who do exist still don't occupy senior positions, relatively speaking. Which, writ large, all means more more caution thrown to the wind, and more economic instability.

The answer seems pretty obvious. As neuroscientist John Coates tells Forbes, "One way of dampening that source of instability in the financial system is to increase the number of women and older men in the markets because they have very different physiology then young males."

Something authors Bronson and Merryman agree with wholeheartedly: "Wall Street is indeed an inefficient labor market. Women are under-hired... Meanwhile, plenty of inaccurate men are being hired, and they are paid hundreds of thousands of dollars for jobs they aren't good at."